Add 'course-of-action:passive=nodiscover'

[andurin]

Hi,

I'm on a use case where we want to search attributes regularly on historical data as some kind of default action for new attributes. On some rare cases we want to exclude specific (noisy) attributes from that default process.

The Course of Action taxonomy would match quiet good here but I would need a specific tag to exclude that noisy IOCs.

What do you think about this change?

Regards, Hendrik

[adulau]

It's indeed a very good point. Thanks for the contribution.